SLA Pro - Powered

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Seth
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Re: SLA Pro - Powered

#121 Post by Seth »

What was the talent at this gig?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#122 Post by Bruce Weldy »

Seth wrote: Sat Mar 13, 2021 2:20 am What was the talent at this gig?
There was no talent....it was me..... :mrgreen:

My buddy Jay on acoustic and I played my Tele through an Ethos pedal straight into the board. We both sang.....mostly old, classic country stuff. As we were doing it, we realized that we play a whole lot of Merle Haggard songs.....

It was fun. Jay and I did this several years ago once, so this was like a first time all over. The owner said we can come every Friday night if we want. We'll probably do one a month.

Next week it's back to Rock and Blues with my other band.....

And just for name-dropping - I'm mixing Sundance Head tonight. He won one of those shows like The Voice. He's the son of Roy Head, who you old guys might remember from the song Treat Her Right in the 60s.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Dale Hammer
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Joined: Wed Apr 04, 2012 1:30 pm
Location: Topeka, Kansas

Re: SLA Pro - Powered

#123 Post by Dale Hammer »

Excellent.

Bruce Weldy
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Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#124 Post by Bruce Weldy »

Time for a little update on the SLA.......the speaker is great. The amp sucks. It cut out several times last night. A little pop, then it stops for a second, then back on. Sounds like some kind of internal limiter.

I ran just the SLA and no T24 this time.....sounds great by itself. But, I do have a separate setting in the DSP for running it by itself, so it's possible that I missed turning off the limiter on that setting - but, I don't think so.

Overall though, I really thought this amp would put out more power than it does. It claims 400 watts at 4 ohms......so, even if I'm only getting 100 watts of real power at 8 ohms, it should be screaming loud. I know the SLA can take a lot more than I was giving it.

If that limiter is off, then I'm scrapping the amp and taking along one of my Crowns to run this thing.

Very disappointing.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Bill Fitzmaurice
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Re: SLA Pro - Powered

#125 Post by Bill Fitzmaurice »

Bruce, if you don't think it's worth recommending I'll pull my posts about it. By your description it sounds like the power supply is inadequate.

Bruce Weldy
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Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#126 Post by Bruce Weldy »

Bill Fitzmaurice wrote: Sat Apr 10, 2021 7:56 am Bruce, if you don't think it's worth recommending I'll pull my posts about it. By your description it sounds like the power supply is inadequate.
That's possible, but I kinda' feel like it's an input limiter......but, you could be right. I guess the power supply could shut down like that too.

It happened whenever we'd both get a little heavy on lower notes E through A on the low E string. Seems like it just was getting too much signal. My mixer was hardly breathing.

Funny thing though, it didn't do this when running through the passive crossover with the T24 - we played through the exact same settings on the gear and mixer.

Of course, I may have a bad unit. It did do this cutting out thing when I was first testing it with just an iPad plugged straight into it playing music if I turned the level on the amp past about 3 o'clock.

May be worth a call the PE to see if they can shed any light.

Wish there was just a straight single channel power amp with one input and a volume knob. As far as I'm concerned, that's what every powered speaker should have - not all the extra channels, buttons and switches to get screwed up.


Side note......seems like every time I have to mix on a powered system - someone has engaged the MIC button on the input instead of LINE. I guess because the MIC input is louder they think it's better.....but, it just distorts much quicker. Too many options in the hands of the un-educated is a bad thing. Did a show two nights ago where every monitor was switched to MIC. Another reason why I like an amp rack and not powered speakers for most applications.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#127 Post by Bruce Weldy »

Ok......did some testing on it this morning.

Ran a 100hz test tone to the SLA via an iPad straight into the amp. Both channels cut out at about 6.5-7 on the volume knob. So, the channels are the same.

Put my voltmeter directly on the amp with no speakers attached. Got 41 volts and didn't see any clipping or limiting as I turned it up.

Put the speakers back in line and measured the voltage. It crapped out at the same place on the volume knob with the meter only showing about 5 volts.

So, the problem is obviously load dependent. My thinking that it was limiting must be wrong as I checked and the limiters were off on my settings and it never had a problem when there was no load.

I feel comfortable with the crossover wiring as the box sounds just fine at lower levels of input. So, I don't think there's a wiring issue. It's wired to the 8ohm specs.

Bill, does that support your opinion that the power supply just can't handle the power needs once there is a load applied?


Odd thing is that this occurred way, way more with just the SLA than with the amp running through the sub, then to the SLA. At the one gig we did with it that way, there were no cutouts. But, it happened too many times to count with just the SLA.....and the volume on the amp stayed exactly the same both times.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Seth
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Re: SLA Pro - Powered

#128 Post by Seth »

I'd be curious to see if it cut out while driving a different speaker
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#129 Post by Bruce Weldy »

Seth wrote: Sun Apr 11, 2021 11:48 am I'd be curious to see if it cut out while driving a different speaker
Well, that's an interesting thought......I can test that because of the way I built the switchable output jacks......think I'll try that....

I knew there was a reason we kept you around..... :mrgreen:

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#130 Post by Bruce Weldy »

Bruce Weldy wrote: Sun Apr 11, 2021 12:00 pm
Seth wrote: Sun Apr 11, 2021 11:48 am I'd be curious to see if it cut out while driving a different speaker
Well, that's an interesting thought......I can test that because of the way I built the switchable output jacks......think I'll try that....

I knew there was a reason we kept you around..... :mrgreen:
I just ran out and tried the same test through a Yamaha SM12IV (the speaker I built the SLA to replace), and it took everything the amp could give. Well, I got to about 9 with the 100hz tone and that was stupid loud - didn't want to take any chances going higher.

So, that seems to be pointing back to the SLA.....What could be happening in the SLA to cause this? It's wired to specs from the plans. 4x6 option. Series/Parallel on the Sixes and the tweeters. There is only a high pass and the problem occurs with lower notes - could it be a wiring issue? I can't imagine it. If it was somehow wired wrong to get 2 ohm load, I doubt that it would sound very good. And I know how it was wired.....

How could I check the impedance of the speaker array?

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#131 Post by Bruce Weldy »

Bruce Weldy wrote: Sun Apr 11, 2021 12:14 pm

How could I check the impedance of the speaker array?
Hey Dumbass, try the ohm meter that's in your voltmeter........

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#132 Post by Bruce Weldy »

Bruce Weldy wrote: Sun Apr 11, 2021 12:21 pm
Bruce Weldy wrote: Sun Apr 11, 2021 12:14 pm

How could I check the impedance of the speaker array?
Hey Dumbass, try the ohm meter that's in your voltmeter........
Good idea.......

I came straight out of the SLA bypassing the power amp. My ohm meter only measures down to a "200" scale. The reading was moving between .7 and .8. So on a "20" scale, that would be 7-8 ohms, correct?

Or, is that registering and actual .8 ohms? I don't see how that could be possible - even if the 4 drivers were parallel, it would only be 2 ohms.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Seth
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Re: SLA Pro - Powered

#133 Post by Seth »

Bruce Weldy wrote: Sun Apr 11, 2021 12:21 pm
Bruce Weldy wrote: Sun Apr 11, 2021 12:14 pm

How could I check the impedance of the speaker array?
Hey Dumbass, try the ohm meter that's in your voltmeter........
+1

:mrgreen:
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Seth
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Location: Sacramento, California, USA
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Re: SLA Pro - Powered

#134 Post by Seth »

Bruce Weldy wrote: Sun Apr 11, 2021 12:25 pm I came straight out of the SLA bypassing the power amp. My ohm meter only measures down to a "200" scale. The reading was moving between .7 and .8. So on a "20" scale, that would be 7-8 ohms, correct?

Or, is that registering and actual .8 ohms? I don't see how that could be possible - even if the 4 drivers were parallel, it would only be 2 ohms.
I think it is what it is. No conversion. So, there's a short or bad component somewhere. Pull the dish and take a look-see.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro - Powered

#135 Post by Bruce Weldy »

Went back and tried the 2k ohms setting and it showed .001 - so it definitely uses the scale as it rounded up from .8 at the 200 scale to register .001 at the 2k scale......so, it looks like 8 ohms is correct.

Thought I'd try another test. Put on some music and ran it through the Yamaha. I was able to take it all the way to 10 with no problem. Same song, just switched over to the SLA and it crapped out again.

Pretty sure something is wrong in the cab that's cratering the amp.......looking for suggestions. And once again.....it sounds great at lower volumes.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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